1. Field of the Invention
The present invention relates to an electronic musical instrument which produces a musical sound with a pitch corresponding to pitch data detected from an input waveform signal, and more particularly to a control apparatus for use in a musical sound production apparatus for controlling a musical sound according to pitch variation information detected from the pitch data.
2. Description of the Prior Art
A type of electronic musical instrument has been developed which detects an oscillation of an activated string of a guitar or the like as an electronic waveform signal, and controls a digital or analog musical sound producing circuit in accordance with the input waveform signal to synthesize a musical sound and produce a sound. On the other hand, the input waveform signal may be formed by electrically detecting an acoustic signal produced by a human voice or an acoustic musical instrument.
The following articles disclose these technologies.
U.S. Pat. No. 4,117,757 (issued on Oct. 3, 1978), inventor: Akamatsu.
This article discloses an electronic circuit which produces a waveform signal whose logical value sequentially reverses between "1" and "0" at positive and negative peak points of the input waveform signal. The waveform signal becomes a rectangular wave signal and its frequency corresponds to the pitch of the input waveform signal.
U.S. Pat. No. 4,606,255 (issued on Aug. 19, 1986), inventor: Hayashi et al.
This article discloses a guitar synthesizer. The apparatus extracts a pitch from every string and thereby provides a corresponding voltage signal and produces a musical signal based on the voltage signal.
U.S. Pat. No. 4,633,748 (issued on Jan. 6, 1987), inventor: Takashima et al.
This article discloses a technology for extracting a pitch through a digital process after converting an acoustic signal input from a microphone into a digital signal.
U.S. Pat. No. 4,688,464 (issued on Aug. 25, 1987), inventor: Gibson et al.
This article discloses a technology for extracting a pitch in accordance with a time interval which is obtained by the input waveform signal crossing three threshold levels comprising a high threshold level, a middle threshold level and/or a low threshold level.
Japanese Patent Publication No 57-37074 (published on Aug. 7, 1982), applicant: Roland Kabushiki Kaisha.
Japanese Patent Publication No. 57-58672 (published on Dec. 10, 1982), applicant Roland Kabushiki Kaisha.
These two articles correspond to the above U.S. Pat. No. 4,117,757 and both disclose a technology for producing a rectangular wave with a frequency corresponding to a pitch of the input waveform signal.
Japanese Patent Disclosure (Kokai) No. 55-55398 (disclosed on Apr. 23, 1980) applicant: Toshiba Corp.
This article, as in the above U.S. Pat. No. 4,117,757, discloses a technology for producing a rectangular wave with a frequency corresponding to a pitch of the input waveform signal.
Japanese Patent Disclosure (Kokai) No. 55-87196 (disclosed on July 1, 1980), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This article discloses a technology for producing a basic wave pulse with a period corresponding to a pitch in accordance with the output of the guitar pick-up, and providing frequency information by counting with an interval counter, and converting the frequency information into digital frequency information.
Japanese Patent Disclosure (Kokai) No. 55-159495 (disclosed on Dec. 11, 1980), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This article disclosed the art which outputs a coincidence signal when adjoining periods extracted from an input waveform signal are almost coincident, thereby resulting in no change in extracted pitch, and indicates a start of sound production in accordance with the coincidence signal.
Japanese Utility Model Disclosure (Kokai) No. 55-152597 (disclosed on Nov. 4, 1980) applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This article discloses a technology for extracting an oscillation of a string using an optical pick-up, causing an oscillation of a string by using a pick-up signal to provide a maintaining effect of an oscillation.
Japanese Utility Model Disclosure (Kokai) No. 55-162132 (disclosed on Nov. 20, 1980), applicant; Keio Giken Kogyo Kabushiki Kaisha.
This article discloses a technology for detecting zero cross points following positive and negative peak points of the input waveform signal to produce a frequency signal corresponding to a pitch with a flip-flop, which is set or reset every time the zero cross point occurs.
Japanese Patent Publication No. 61-51793 (published on Nov. 10, 1982), applicant: Nippon Gakki Seizo Kabushiki Kaisha.
This article is a patent publication corresponding to the Japanese Patent Disclosure (Kokai) No. 55-87196 and the subject matter thereof is the same as the content of the Japanese Patent Disclosure (Kokai) No. 55-159495. Namely, the present article discloses a technology for producing digital frequency information by detecting substantial concidence of adjacent periods extracted from the input waveform signal.
Japanese Utility Model Disclosure (Kokai) No. 62-20871 (published on May. 27, 1987), applicant: Fuji Roland Kabushiki Kaisha.
This is the Japanese Utility Model Publication corresponding to the above U.S. Pat. No. 4,606,255.
Japanese Utility Model Disclosure (Kokai) No. 61-26090 (disclosed on Feb. 5, 1986), applicant: Seikou Denshi Kogyo Kabushiki Kaisha.
This article discloses a technology for obtaining exact pitch information by detecting a pitch from the input waveform signal and sequentially writing it into a memory and thereafter obtaining accurate pitch data through an arithmetic operation.
Japanese Patent Disclosure (Kokai) No. 62-163099 (disclosed on July 18, 1987), applicant: Fuji GenGakki Seizo Kabushiki Kaisha.
This article discloses a technology relating to a guitar controller for use in a synthesizer. This is a technology for switching a method of changing a frequency, depending on whether the sound to be performed is a single sound or plural sounds. For a single sound, a picked-up oscillation period is caused to be reflected onto a musical sound to be continuously produced as it is, and for plural sounds the picked-up frequency period is caused to be reflected chromatically onto a musical sound in chromatic scale steps.
Further, the U.S. patent applications which are assigned to the present assignee and relate to an electronic string musical instrument or a related electronical apparatus are as follows.
U.S. Ser. No. 112,780 (filed on Oct. 22, 1987), inventor Uchiyama et al.
This article discloses a technology for measuring a time period between positive and negative peak points, or a time period between zero cross points related to the peak points, and extracting the peak based on the measured time period, and performing various controls in accordance with the extracted peak.
U.S. Ser. No. 184,099 (filed on Apr. 20, 1988), inventor: Iba et al.
This article discloses a technology for designating a parameter of a musical sound such as a timbre by operating a fret and picking a string. This technology extracts a pitch and detects the operated fret by a fret switch.
U.S. Ser. No. 256,398 (filed on Oct. 7, 1988), inventor: Iba et al.
This article discloses a technology for controlling a musical sound production with regard to respective strings, varying a characteristic of the output musical sound according to the strength at which a string is picked, or actuating an effector or pan (localization in sound filed).
U.S. Ser. No. 252,914 (filed on Oct. 3, 1988), Inventor: Uchiyama.
This article discloses a technology for changing a pitch extraction circuit from a conventional analog circuit to a digital circuit, to facilitate integration of the circuit.
U.S. Ser. No. 256,400 (filed on Oct. 11, 1988), Inventor: Matsumoto.
This article relates to an electronic apparatus for extracting a pitch from an input waveform signal and for producing a musical sound having that pitch, and discloses a technology for changing a pitch of an output sound in accordance of a variation of the pitch of the input waveform signal and for deleting an unnecessary variation of an interval.
U.S. Ser. No. 282,510 (filed on Dec. 9, 1988), Inventor: Obata.
This article discloses a technology for starting a musical sound production whose interval is accurate and stable and for instructing start of a musical sound production in a chromatic manner, based on a pitch extracted from a pitch extraction means.
U.S. Ser. No. 290,981 (filed on Dec 28, 1988), Inventor: Murata et al.
This article discloses a technology for electronically performing a perfect tuning of a string. Namely, it discloses a technology for determining a reference pitch by pressing a string onto a predetermined fret and picking the string before a performance and, based on a reference pitch, determining the pitch of the produced musical sound from period information obtained by the picking at the designated fret.
U.S. Ser. No. 329,418 (filed on Mar. 27, 1989), Inventor: Obata.
This article discloses a technology for detecting a signal strength at a point of a rising of an input waveform signal and a degree of variation of the signal strength and for enabling a volume of a musical sound or timbre to be controlled independently by those two parameters. This technology makes it possible to vary only the timbre without changing the volume of the musical sound, for example, by shifting the position at which the string of an electronic string musical instrument is picked.
Where an electronic musical instrument is realized by using the above recited prior art, a pitch frequency is extracted from an input waveform signal and a musical sound production circuit produces a musical sound having pitch corresponding to the pitch frequency. However, if such a musical instrument can be realized as, for example, an electronic guitar, the following problems are observed.
Where a performer intentionally changes the pitch frequency of an input waveform signal by a choking method or by a tremolo arm operation, the performer can change the pitch of the produced musical sound in accordance with a variation in pitch, but cannot change the timbre or volume of the musical instrument. Therefore, there is a problem that a variety of musical expression cannot be achieved.